Semiconductor integrated circuits (IC) are widely used in a large variety of applications. The impressive progress in technology has allowed the integration of many functions, i.e. logical, data storage, parameter and/or motion sensors, etc. Correspondingly a wide variety of semiconductor ICs are produced, such as micro-processors, volatile and non-volatile memories, micro-electro-mechanical devices, embedded products, and others.
Typically many (from a few hundred to some thousands of) IC chips are realized on a wafer, such as a silicon wafer. The improved control on processing technology has lead to a miniaturization of the elementary electronic components, so that current ICs including more than 1 billion transistors are available, the maximum number being essentially limited by the chip size on the wafer and economic considerations based on a corresponding achievable yield. However, in many other cases ICs are much smaller, so that typical chip size may range from about 1 mm2 to about 2 cm2 (these figures are not absolute limits).
In all cases both cost and reliability are fundamental parameters to be considered together with functionality and performance. Reliability is affected by several variables such as contaminants entering the IC device. To limit such an occurrence, a top passivation layer is usually formed on the IC chip, however the finishing at the chip's edge sidewalls is a potential source of contaminants. This problem is particularly severe in those applications in which the IC is directly assembled on a board without additional assembly or package to further protect the semiconductor chip (this often occurs when space and/or weight constraints are important, such as in mobile phone apparatuses). Overall cost is not only affected by chip area but also by wafer area not useful in the final product, such as inter-dice separation scribe lanes that, despite necessary, can be viewed as wasted wafer area; which is more important in the case of small sized IC chips.